Methods and apparatus for wireless network load generator clustering

ABSTRACT

Methods and hardware for combining multiple, independent, wireless station (or user) emulating, load generators into a cluster, which is a group of independent wireless network load emulators working together to provide arbitrarily large, coordinated 802.11 user communities. A single command, control, and reporting mechanism establishes connections to the load generator nodes making up the cluster, distributes work to the nodes, and collects statistical data from the nodes. Alternate routing simplifies the routing of commands, control requests, and requests for statistical results when only a single load generator node is addressed.

CROSS-REFERENCE TO A RELATED APPLICATION

This application is entitled to, and claims, the benefit of the 29 Dec. 2003 filing date of provisional application No. 60/533,290.

TECHNICAL FIELD OF INVENTION

The present invention relates generally to the field of data communications and, specifically to the testing of wireless networks. This invention can be used to advantage by wireless network development engineers, network administrators, and network performance testing organizations.

BACKGROUND OF INVENTION

Many, including development engineers, network administrators, and network testing organizations, have occasion to test the performance and scalability of wireless networks. The accepted practice for testing wireless networks is to install numerous computers with wireless network capability. This common practice is expensive as it driven by the cost of the many necessary computers, and the test setup is not easily configurable for a variety of user population sizes and data traffic loads.

There is accordingly an existing and continuing need for methods and hardware for testing wireless networks, which have the capability of significantly reducing the cost of the testing and which easily accommodate a wide variety of user populations and traffic loads.

SUMMARY OF THE INVENTION

Such needs are met by the present invention which establishes a method of, and provides hardware for, combining multiple, independent, wireless load generators, which emulate wireless stations, into a coordinated network called a cluster. The cluster of independent wireless load generators operates as a single system. Because this cluster is composed of independent load generators nodes, the cluster can be scaled to the load necessary to test the wireless system under test by adding and/or removing nodes in the cluster.

The objects, features, and advantages of the present invention will be apparent to the reader from the foregoing and the appended claims and as the ensuing detailed description and discussion of the invention proceeds in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a typical clustering environment comprising a command, control, and reporting computer connected to a collection of independent load generators and a single wireless system under test (such as a wireless switch or access point) in accord with the principles of the present invention; and

FIG. 2 is a block diagram illustrating the functional relationship among the components of the load generator cluster.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows, in block diagram form, a wireless network load generator cluster 100. This load generator cluster consists of a command, control and reporting computer 102 connected to an 802.3 hub 104. Load generator nodes 106 that each emulate up to 64 virtual 802.11 stations 108 are connected to hub 104 via 802.3 connections 110. Representative nodes 106-1, 106-2, and 106-n and corresponding connections 110-1, 110-2, and 110-n are shown in the drawings.

The total number of load generator nodes 106 in the cluster is both variable and scalable as indicated vertical dotted line 112.

Each emulated virtual station 108 communicates via an 802.11 wireless connection with the wireless system 116 under test. Representative connections 114-1, 114-2, and 114-n are shown in the drawing.

Each load generator node 106 controls a user population of up to 64 virtual stations 108 as disclosed above. Each wireless network load generator cluster 100 has and controls up to some arbitrary number of load generator nodes 106.

Referring next to FIG. 2, a clustering meta-process system 198 within the command, control, and reporting computer 102 (FIG. 1) is responsible for load generator node management and coordination. The cluster process is instantiated—i.e., initialized and made ready to accept work requests as described below—using a list 200 enumerating the IP addresses of the load generator nodes 106 that will form cluster 100. Thus, the node list uniquely identifies each of the wireless node generators in a cluster. These nodes are not part of meta-process system 198.

A new node 106 is added to cluster 100 by physically connecting it to the cluster and informing the cluster that the new node exists. This may be done by way of a work request or by providing a new node address list 200.

To remove a node from cluster 100, it must be removed from node address list 200 before cluster 100 is instantiated or removed by using a work request. Once the node is removed from the clustering meta-process system 198, it may be physically removed.

For each node 106 in node address list 200, the cluster process system 198 maintains two 802.3 connections. Specifically, a command and control connection management subsystem 202 manages a command and control connection 204 to each node 106. A reporting connection management subsystem 206 manages a reporting connection 208 to each node 106. Once all connections are established, load generator cluster 100 becomes operational.

Work requests 210 for cluster 100 are received by cluster interface 212, forwarded through connection 214 to work management and distribution subsystem 216, and distributed to constituent load generator nodes 106 by the work management and distribution subsystem 216 through connection 218, the command and control management subsystem 202, and connections 204.

A work request is an operation to be performed by cluster 100. This work request may come from the human user directly using the cluster interface 212 or from a software program using the cluster interface. Exemplary work requests might create 5000 emulated wireless users, bring all emulated users to the 802.11 associated state, and/or instruct all emulated wireless users to begin sending and receiving data.

Statistical results are collected from the constituent load generator nodes 106 by the clustering process via reporting connections 208 and reporting connection management subsystem 206, transferred to work management and distribution subsystem 216 through connection 220, and then routed to cluster interface 212 through connection 214. The statistical results are standard 802.11 statistics that a load generator collects. These include, among others, various 802.11 frames, transmitted/received errors, and data transfer rates.

Work requests 210 received by cluster interface 212 that address a specific node 106 bypass the work management and distribution subsystem 216 and communicate directly with that specific node through connection 222, command and control connection management subsystem 202, and command and control connection 204 for commands and control requests and through connection 208, reporting connection management subsystem 206, and a reporting connection 226 for statistics.

The present invention, as described above is unique in that it provides, among other advantages:

-   -   1. arbitrarily large, coordinated communities of 802.11 wireless         virtual stations for scalability and performance testing of         802.11 wireless systems including, but not limited to,         enterprise-wide wireless networks, metropolitan-wide wireless         networks, wireless local area network switches, and access         points;     -   2. a mechanism for adding, removing, and reconfiguring wireless         virtual user capabilities as new capabilities are developed and         deployed, while preserving investment in and capabilities of         existing deployed systems;     -   3. a single point of command, control, and reporting         capabilities;     -   4. a mechanism for testing diverse wireless network topologies;     -   5. a mechanism for testing geographically dispersed, wireless         network access points.

The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description; and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. 

1. A scalable system for testing a wireless communication system, the testing system comprising: a cluster of independent, wireless, load generator nodes which operate as a single entity and which can be added to and removed from the cluster; each of the load generator nodes having the capability of emulating and controlling one or more virtual wireless stations.
 2. The combination of a scalable testing system as defined in claim 1; and a wireless connection between each emulated virtual station and a wireless system under test.
 3. The combination of a scalable testing system as defined in claim 1 and a computer for managing and coordinating the operation of multiple load generator nodes.
 4. The combination of a scalable testing system as defined in claim 1; a command and control connection to each node; and a command and control management system for managing the command and control connections.
 5. A combination as defined in claim 4; and a work management and distribution system for distributing to load generator nodes in the cluster via the command and control management system a request for work by the load generator nodes.
 6. The combination of: a scalable testing system as defined in claim 1: a reporting connection to each node; and a reporting connection management system for managing the reporting connections.
 7. A method for testing a wireless communication system which comprises the steps of: providing a cluster of independent, wireless, load generator nodes which operate as a single system and which are each capable of emulating up to n virtual wireless stations; instantiating the process with a list of addresses corresponding to the load generator nodes; and establishing and maintaining a wireless command and control connection and a reporting connection to each load generator in the node list.
 8. A method as defined in claim 7 which comprises the step of providing a work management and request distribution system to distribute work requests to the load generator nodes via the wireless command and management connections and to forward statistics via wireless reporting connections.
 9. A method as defined in claim 7 which includes the step of bypassing the work management and request distribution system and forwarding directly to a particular load generator node through its wireless command and management connection work requests addressed specifically to that node and statistics collected from the node.
 10. A method as defined in claim 7 which includes the step of establishing and maintaining wireless connections between the emulated user and the wireless system under test. 